HEAT TRANSFER TUBE AND METHOD OF MAKING SAME

摘要

Improved heat transfer tube has radial longitudinal fins on a central core and radial transverse fins on its exterior surface. The composite tube is made by the steps of inserting a longitudinally finned core member inside a smooth surfaced outer tube and then subjecting the outer tube to an external finning operation which produces external fins on the tube while reducing the internal tube diameter of the tube sufficiently that the tube will be firmly mechanically bonded to the finned core member.